Flow valve



Dec. 9, 1941A. l w. R. GobsEY Erm. 2,265,836

FLOW VALVE Filed April 15, 1940 INVENTO -W Patented Dec. 9, 1941 UNITED STATES PATENT OFFICEl aantastL i FLOW VALVE Wilbur R. Godsey and William Horn, Kilgore, Tex., assignors to Oil Lift Supply Company,

re, Tex., a corporation of Texas Application April 15, 1940, Serial No. 329,693

(Cl. S-233) 9Claims.

This invention relates to valves usedfor unloading or flowing a well by what is known as the gas lift method, which is employed where the formation pressure is insufilcient to flow the liquid up through the well to the surface of the earth and in which, therefore, some form of pumping or lifting operation is necessary to produce the ow.

In the gas lift method of flowing wells, gas under pressure is forced either into the casing or into the tubing of a well to cause the flow. For example, the gas may be forced into the casing around the outside of the tubing and the tubing used for flowing the well, the gas .pumped into the casing forcing the oil level down therein and up into the tubing until finally the gas will pass below the lower end of the tubing, and into the tubing to force the oil out of the tubing to the surface of the ground.

In many cases, however, it is desirable, if not necessary that the gas be admitted to the tubing at spaced pointsalong its length and various types of valves have been devised for admitting the gas at spaced points along the tubing. One such type, known as a kick-oil valve, is intended to admit gas under pressure from the casing into the tubing at a predetermined point to force the oil in the tubing above that point out of the top of the well, thus lightening the column of oil in the tubing., Such valves may be used at spaced points along the length of the tubing so that with a. relatively low gas pressure it is possible to unload the tubing in stages.

The upper valves in such a system may be known as kick-olf orunloading valves, but any valve in such a seriesmay act as the flow valve. Thus, when the gas under pressure-is admitted into the casing and serves to lower the level of liquid standing in the casing to a point below the uppermost valve, gas will then be admitted into the tubing at this point.V The gas so admitted will lighten the column of fluid above this valve and if the valve remains open and the well pressure is insufficient to cause the iluid to flow into the tubing as fast as it is being unloaded Vby the gas entering through the uppermost valve,

the oil above the uppermost valve will be unloaded and the uppermost valve should then be closed. 'I'he iluid level in the casing will then again be lowered by the pressure of gas in the casing and the process repeated through the enter the tubing as fast as it is being unloaded from the tubing, therewill be a column of oil constantly rising past the valve through which the gas is entering. This column will be constantly aerated by that gas entering through that valve and the well will be kept flowing. The

valve through which the gas is entering will in such instances be operating as a flow valve.

'I'he object of the present invention is to provide' a new type valve such as above referred to and one which will be simple to manufacture,`

easy to adjust, and eilicient in operation.

One form of the invention is illustrated in the accompanying drawing in which:

Fig. l is a longitudinal'section through th casing of a well showing the dispositiontherein of unloading and flow valves in accordance with this invention.

Fig. 2v is a longitudinal section through a section of the tubing shown in Fig. 1 illustrating the manner of mounting the valves thereon.

Fig. 3 is a side elevation of the structure shown in Fig. 2.

Fig. 4 is an enlarged longitudinal section through a flow valve constructed in accordance with this invention illustrating' the'same in open position.

Fig. 5 is a view similar to Fig. 4 but showing the valve in closed position.

Referring speciiically to the drawing, 6 indicates a well casing and 'I a string of tubing therein, these parts being provided with the usual or suitable Christmas tree connections indicated as pressure is suiicient to cause the well iluid-to a whole at 8 for flowing ofi the oil and for admitting gas under pressure to either the casing or the tubing, according to the manner in which the apparatus is used.

At spaced points along the tubing, one section of which is shown in Figs. 2 and 3, a series of valves are placed, constructed according to the present invention. Each valve indicated as a whole at 9 is set at the top into a boss I0 which may be Welded or otherwise secured to the tubing section and held at the bottom in a xture II welded or otherwise secured to the outside of the tubing section. The boss I0 has a port I2 which connects the upper endof the valve casing with the interior of the tubing. p

'I'he valve comprises an upper cylinder I3 threaded to a screw y connection I 4 which is screwed into the boss I Il as indicated at I5. At its lower end the connection I4 is provided with a seat ring I6 cooperating with a tapered plunger valve I1 having a collar or shoulder I8 which stops against a ring I9 iixed in the cylinder I3,

until the second valve is and having a small port 20 therein. An inlet port 2| extends through the cylinder I3 at a point adjacent the valve I1. The valve stem 22 works, through th'e ring |9 and at its lower end is reduced as indicated at 23 and threaded to receive'nuts 24 working in a recess 25 in a coupling 26. A spring 21 is coiled around the stem 22 and is held in compression between the ring I9 also through a ring 33 iixed in the lower cylinder 3D, with a collar 34 which stops against the ring 33 to limit the downward motion of the rod. A spring 35 is coiled around the plunger rod 3| in compression between the ring 33 and adjustable nuts 36 threaded on the lower end of the rod 3|. The upper end of the plunger rod `3| bears against the lower end of the stem 23 when the stem 23 is in open position or is being closed, and the ring 33 is provided with a port 31 to connect the upper chamber in the cylinder 30 with the open lower end of the cylinder and hence with the space within the well' casing.

Valve structures thus described are assembled in series at various selected points along the tubing l, as above indicated, from some point below the static iluid level of the well to some predetermined point adjacent to the bottom of the well. The spacing and location of these valves depend on many factors, including the pressure of the gas supply available and the characteristics of the particular well.

In operation tubing carrying the valves reerred to is lowered into the well and naturally the liquid in the well will rise in the tubing to the same level as in the casing. The gas under pressure will then be forced into the casing and will serve to depressthe level of the liquid in the casing and cause the level in the tubing to rise until the level in the casing falls below the uppermost valve in the series. V'I'he valve |1 oeing normally open, gas in the casing will be forced through the port 2| into the valve, and thence through the passage I2, and will serve to lighten the oil above the valve and begin the unloading operation. This gas will be fed at a rate which will aerate but not necessarily fast enough to form a gas piston underneath the column of oil. If the well is capable yof producing rapidly enough at this level to keep feeding the oil up through the tubing and Iprevent further lowering of the level in the casing., gas will continue to feed through said uppermost valve which will under such circumstances act as a flow valve. If, however, the well has insufcient capacity at such a high level to continue producing, the level in the casing would be forced down by the gas reached. During this time it is desirable that the valve be of such a nature that it will remain open until the level of liquid in the casing approaches the second valve. In other words, the uppermost valve should be hard to close or should require a relatively high differential between the pressure in the casing and that in the tubing at the valve.

After the closing of the first valve the flow should take place through the second valve in the same manner as previously in the first valve.

This should continue until a level is reached at decreases. lconstant pressure acting on the area of the which the well will produce asfast as it is being unloaded or until the level in the casing falls below the lowermost valve. In any case, moreover, the upper valves must not only be of such a nature that they will be hard to close, but they must also be of such a nature that at no time will the column of liquid above them be sufllcient to cause them to reopen once they have closed.

Now the lowermost valve is termed a flow valve as distinguished from an unloading valve because its primary purpose is to keep the well flowing as distinguished from unloading the static column of liquid in the well. This lowermost valve should be set so that immediately when the differential becomes a little greater than it should be it will close and shut off flow of gas to the tubing. On the other hand, as soon as the differential drops by virtue of flow or oil into tubing from the well by any substantialV amount, this valve should then again open and aerate the fluid to cause it to flow from the well.

In the valve which is being discussed here, the valve is normally held open by vmeans of the spring which surrounds the valve element. The spring which surrounds the auxiliary plunger 3| has no direct eiect on the valve at any time. Its only eiect is to act against the force on the auxiliary plunger rod 3| that tends to close the valve. This valve would therefore normally stand open when the pressures within and without the tubing are equalized;

Now, assuming that the valve in question is the uppermost valve of a series of unloading valves, the valve would remain open until the liquid level in the casing is io'rced down past this valve. At this point the gas would start entering through the valve and this gas would aerate the column in the tubing above the valve so as to assist in unloading this column. Assuming that the well flow is insufiicient to maintain this level in the casing, the level in the casing would continue to be lowered until a point is reached adjacent the next lower valve. During this time the differential on the uppermost valve will be increasing because the casing pressure will remain the same and the column of liquid above the uppermost valve will be lightened and unloaded by the gas entering through this valve. This increase in differential will cause aV greater flow through the uppermost valve and the throttling effect at the port 2| of t valve will cause a reduction oi! the pressure within the upper portion of the cylinder |3. Since the upper and lower portions of cylinder |3 are in communication through the port 20 and there is no substantial ow through port 20, the pressure in the lower part of cylinder I3 will also be lowered to the same value as that in the upper portion. The .pressure in the cylinder |3 normally acts on an area equal to the cross section of the auxiliary plunger 3| tending to hold the same against movement in a direction to close the valve, and as this pressure drops its eiect on this plunger tending to -hold it in such position At the same time there lwill be a plunger 3| tending to close the valve. As this differential increases the tendency for the valve to closewill increase. The force tending to close the valve however will be opposed not only by the spring surrounding the valve element but also by the spring surrounding the plunger 3|. The valve will thus remain open until a subv stantial differential oi pressures is established. A

Ihe valve will then move quickly to a closed position and when the valve is seated there willbe a diiierential of pressures established between the interior of the tubing and the cylinder I3. The pressure in this cylinder will become equal to casing premure, whereas a pressure relatively the area of the auxiliary plunger 3| and the auxiliary plunger will under the influence of its spring 35 return to the position which it occupied when` the valve was open. It will now be seen that the only forcestending to open the valves will be those due to the pressure in the tubing and the spring surrounding the valve element, whereas the onLv force holding it shut 4will be the casing pressure. This will make the valve hard to open once it is closed. That is, the pressure' in the tubing must rise imtil it exerts onthe valve element enough force so that taken with the force exerted by the spring around the valve element it will overcome lthe casing pressure. Thus,'the tension on the spring 21 alone will determine the opening dlil'erential whereas the closing diierential is determined by the tension on both springs 21 and 35.

in the same, and a gas inlet valve controlling the iiow of gas from the interior of the casing into the tubing, said valve being provided with a resil- -ient means to normally hold it in open position and 'with a pressure actuated plunger separate from and independently movable with respect to -said valve element and adapted to act upon and y close the same underV predetermined conditions moved the diilerential oi pressure acting upon' conditions of dilerential of pressure between the casing and the tubing.

The unloading valve will thus be hard to f close (it will require a high diierential to close it) and hard to open (it will require a low diiferential to open it). The other unloading valves will be similarly adjusted.

Theow valve at the lower end of the string of tubing will be Vadjusted so that it will close when the differential becomes a little greater than it should be (that is, when the amount of 0 liquid being fed into the tubing becomes less than that'discharged) but when the diiterential is reduced a relatively small amount as when the fluid again begins to rise in the tubing, the

valve win reopen to discharge this fluid. This '45 is accomplished with the same type of valve as used for the unloading valves, merely by varyingA the adjustments on the two springs. In the ow valve the springs surrounding the valve element would be placed under argreater tension than 50- in any unloading valve, whereas the spring sur- A rounding the auxiliary plunger would be left under relatively smaller tension. With this adjustmentthe springs surrounding the valve element would have a greater eil'ecttending to open 5 the valve and this would increase the diierential at which the valve would onen, whereas the spring `surrounding the auxiliary plunger would have less eiect in retarding the closing of the valve, thus maln'ng the valve close at a smaller diierentlal.` Y,

It will be seen therefore that a valve has been produced which can be very accurately regulated both as. toits opening and closing characteristics and that the opening and closing characteristics Amay `be adjusted independently of each other. It will further be apparent. that a valve has been provided which is capable of use both as a kick-ofi or unloading valve and as a ilow valve, Vand thatthis valve is capable of achieving all oi th'e objects sought by this invention.

We claim: l

1. In a gas lift apparatus for flowing wells, the combination of a well casing, a well tubing withof diierential of pressure between the casing and the tubing.' Y

2. 'I'he combination of a well casing, a well tubing therein. and a gas inlet valve mounted on the tubing, within the casing, said valve comprising a reciprocating valve member, -a spring coiled around said member and tending to open the same, and a pressure actuated plunger separate from and Yindependently movable withv respect to the said valve element and adapted to act upon and 'bear againstl said member and adapted to-close the same under predetermined 3. In a gas lift apparatus for iiowing wells, the combination of may be supplied under pressure, Va well tubing within the casing, and a valve controlling the iiow of -gas from the casing into the tubing, said valve comprising a surrounding an outlet in one end thereof and a side inlet port, a. reciprocating member in the cylinder cooperating at one end with said seat, a spring operatively connected to said member and tending to. hold the same in open position,

and a pressure actuated plunger separate from and independently movable with vrespect to thev said valve element and adapted to act upon and bear against the other end of said member and tending to close the samel when the diierential pressure exceedsthe resistance of the spring.

4. A valve for use in admitting gas under pressure into an upright liquid dow conduit comprising a member having a passage communicating with the interior of said liquid conduit, a movable valve element adapted to close said opening, resilf ient means for urging said valve element toward Y open position, and means separate from and inl dependently movable with respect to said valve element and actuated by the diierential of pressure between the interior of vsaid liquid conduit and the gas being injected into said conduit to move and to thereby force said valve element to closed position against the tension of said resilient means when said pressure diierential reaches a predetermined maximum.

5. A valve for controlling the admission o'f gas under pressureto an upright liquid flow conduit comprising a member having a passage communicatingwith the interior of said liquid conduit, a valve element movable to close and open said passage, a resilient means for vconstantly urging said valve element toward open position, means separate from and independently movable with respect tosaid valve element and actuatedby the diierential between the pressure within said liquid conduit and the pressure of the gas `being admitted thereto when said valve element is in open position for itself moving and therebycausing movement of said Avalve element to closed posio tion against the tension of said resilient means when said pressure differential exceeds a predetermined amount, and means in addition to said resilient means for resisting such movement of said pressure differential responsive means.

,6. A valve for controlling theadmis'sion of gas a well casing into which gas cylinder having a valve seat under pressure .to an upright liquid-flow conduitAV comprising a member having a passagecommunieating with the interior of said liquid conduit, a

valve element movable to close and open said passage, a resilient means for constantly urging said valve element toward open position, means separate from and independently movable with respect to said valve element and actuated by the diierential between the pressure within said Y liquid conduit and the pressure ofthe gas being admitted thereto when said valve element is in open position for itself moving and thereby causing movement of said valve element to closed `position against the tension o! said resilient means when said pressure dilerential exceeds a predetermined amount, and a second resilient means opposing such valve closing movement of said pressure responsive means.

7. A valve for controlling the admission of 'gas under pressure 'to an upright liquid flow conduit comprising a member having a passageway for admitting such gas to said conduit, a movable under pressure to an upright liquid ow conduit comprising a member having -a passageway for conducting such gas to said conduit, a movable valve element subject when closed to the `pressure diierential between the interior of said conduit and said gas to retain said valve in closed position, resilient means urging said valve toward diferential at which said means valve element adapted to close and open said passageway, a resilient member urging said valve tial between said pressures exceeds a predetermined 8. A valve for controlling the admission of gas open position for opening said valve when said pressure diiferential fails below a predetermined minimum, means separate from and independently movable with respect to said valve element and in addition to said valve and subject to the pressure dilerential between the interior of said conduit and said gas when said valve is open to engage said valve and move it to closed position against the tension of said resilient means when. the pressure differential exceeds a predetermined maximum, and means for varying the ellect of said pressure dilerential on said last mentioned means to predetermine the maximum pressure will operate to close'the valve.

9. In a valve for controlling the admission of gas .under pressure to an upright liquid conduit comprising a member having a passage therethrough for the flow of such gas into said conduit,

a valve element movable to close andopen said passage, means acting upon said valve element to move the same to open position when the pressure differential between the interior ot said con-- duit -and said gas falls below a predetermined minimum, and other means separate from and independently movable with respect to said valve element for moving said valve element from open .to closed position when said pressure differential exceeds a predetermined maximum.

WILBUR R. GODSEY. WILLIAM HORN. 

